Confessional Lutheranism is a name used by some Lutherans to designate themselves as those who accept the doctrines taught in the Book of Concord of 1580 (the Lutheran "confessional" documents) in their entirety because (quia) they are completely faithful to the teachings of the Bible. While most Lutheran denominations find the basis of their faith in the Book of Concord, Confessional Lutherans maintain that faithfulness to it requires attention to how that faith is actually being preached, taught, and put into practice. Confessional Lutherans believe that this is a vital part of their identity as Lutherans.

Though there are some churches in the Evangelical Lutheran Church in America which would call themselves "confessional," many of said churches have decided to leave the ELCA due to the liberal leanings of the denomination, most notably their stances expressed in the 2009 ELCA convention.[8] The ELCA as a whole does not use the title "confessional" to describe itself, but it and the other member churches of the Lutheran World Federation do ascribe to the unaltered Augsburg Confession and the other confessional documents in the Book of Concord as true interpretations of the Christian faith.[9]

"Quia" versus "Quatenus" subscription[edit]

Lutheran church bodies and Lutheran individuals that identify themselves as confessional hold to a "quia" (Latin for "because") rather than a "quatenus" (Latin for "insofar as") subscription to the Book of Concord. Quia subscription (the Book of Concord is adhered to because it is faithful to the Scriptures) implies that the subscriber believes that there is no contradiction between the Book of Concord and the Scriptures. Quatenus subscription (the Book of Concord is adhered to insofar as it is faithful to the Scriptures) implies that the subscriber leaves room for the possibility that there might be a contradiction of the Scriptures in the Book of Concord in which case the subscriber would hold to the Scriptures against the Book of Concord.[10] Some Confessional Lutherans maintain that this distinguishes them from other ("mainline") Lutheran bodies and Lutherans, who, they believe, hold to a quatenus subscription.

^WELS Topical Q&A: Religion - Roman Catholic, stating: "All popes hold the same office over the church and promote the same antichristian belief so they all are part of the reign of the Antichrist. The Bible does not present the Antichrist as one man for one short time, but as an office held by a man through successive generations. It is a title like King of England"